Testing Stenting and Flow Diversion Using a Surgical Elastase-Induced Complex Fusiform Aneurysm Model

BACKGROUND AND PURPOSE

Rabbit elastase-induced saccular aneurysms have been commonly used for preclinical testing of endovascular devices, including flow diverters. However, all tested devices have been shown to be capable of aneurysm occlusion with this model. We aimed to create a more challenging model to test and discriminate among neurovascular devices of varying efficacies.

MATERIALS AND METHODS

With a surgical approach that included elastase infusion and balloon dilation, we attempted the creation of complex fusiform aneurysms in 16 rabbits, with standard saccular carotid aneurysms created in 15 other animals. Aneurysms were randomly allocated to one of the following treatments: flow diversion (n = 8), high-porosity stent (n = 6), double high-porosity stent (n = 5), and control (n = 6). Angiographic assessment and pathologic analyses were performed at 3 months.

RESULTS

Creation of complex fusiform and standard saccular aneurysms was successful in 12/16 and 13/15 attempts, respectively. All saccular (n = 4) or complex fusiform (n = 4) aneurysms treated with flow diverters were successfully occluded. Three of 3 saccular compared with 0/2 complex fusiform aneurysms were occluded by double high-porosity stents. One of 3 saccular and 0/3 complex fusiform aneurysms were occluded by a single high-porosity stent. Both aneurysm types shared the same pathologic findings when untreated: The aneurysm wall lacked an elastic layer and smooth muscle cells, while the lumen was lined with neointima of varying thickness. Neointimal coverage of the devices was complete when aneurysms were occluded, while leaks were always associated with aneurysm remnants.

CONCLUSIONS

Challenging fusiform aneurysms can be created in rabbits by using a surgical modification of the elastase method.

Walking, Sedentary Time and Health-Related Quality Life Among Kidney Transplant Recipients: An Exploratory Study

OBJECTIVES

The primary objectives of this study were to: 1) establish walking and physical activity prevalence and sedentary time estimates; and 2) determine associations of health-related quality of life (HRQoL) with objectively assessed walking, self-reported physical activity, and sedentary time among kidney transplant recipients.

METHODS

Using a cross-sectional design, kidney transplant recipients received a survey package containing measures of sedentary time, moderate-to-vigorous physical activity, and HRQoL, and a step pedometer.

RESULTS

Thirty-two participants returned a completed survey, for a response rate of 82% (32 of 39 interested participants). The average steps per day were 9752 steps (SD = 3685) and 59% achieved public health guidelines of at least 150 minutes of moderate-to-vigorous physical activity per week. Total sedentary time during the week was 11.6 h/d whereas total sedentary time during the weekend was 8.9 h/d. Compared to those not achieving at least 10,000 steps/d, respondents who were achieving at least 10,000 steps/d had a significantly higher physical component score for HRQoL (Mdiff = 7.8, P = .018). Similar patterns emerged for meeting physical activity guidelines and sedentary time.

CONCLUSION

For kidney transplant recipients, greater participation in walking, overall physical activity, and lower engagement in sedentary activity, was associated with better HRQoL.

Validation of graph-theoretical methods for pattern identification in public health datasets

Pattern identification issues are commonly used in public health practice to identify disease clusters and tendencies towards clustering. The basic building blocks or units for such patterns may be individuals or geographical units, but the key factor is the association between units in terms of time, space or other complex links. A range of methods has been developed for cluster detection but these methods are not designed to handle complex pattern searching. This paper describes early work in developing a novel method of tackling this problem, using graph theoretical techniques developed for computational chemistry. A modified version of the maximum common subgraph isomorphism method was used to search and retrieve enumeration districts (EDs) using 27 user-defined patterns from a set of 106 EDs. The results were then checked manually to ensure that all the appropriate and no additional patterns and EDs were retrieved. The program successfully retrieved all the relevant patterns and EDs and did not retrieve any patterns not specified by the query patterns. This study demonstrates the applicability of using graph theory for identifying and retrieving patterns in public health datasets.

Neonatal infections with multidrug-resistant ESBL-producing E. cloacae and K. pneumoniae in Neonatal Units of two different Hospitals in Antananarivo, Madagascar

Background

We investigated the molecular mechanism of ß-lactam resistance in extended-spectrum ß-lactamase (ESBL)-producing Enterobacterial strains isolated in neonatal units of different hospitals in Anatnanarivo, Madagascar.

Methods

Bacteria were identified by standard biochemical methods, disc diffusion antibiograms and Etest. Resistance genes were sought by PCR. Strains were characterized by Rep-PCR (Diversilab), plasmid analysis and rep-typing.

Results

From April 2012 to March 2013, 29 ESBL-producing E. cloacae and 15 K. pneumoniae were isolated from blood culture (n = 32) or gastric samples (n = 12) performed at day 0 or 2 from 39/303 newborns suspected of early neonatal infection. These infants were treated with expanded spectrum cephalosporins, due to lack of carbapenems, leading to a high mortality rate (45 %). Isolates recovered were all, but 4, multidrug resistant, particularly to fluoroquinolones (FQ) except for 21 E. cloacae isolates. Isolates produced TEM-1 and CTX-M-15 ß-lactamases and their genes were located on several self-transferable plasmids of variable sizes sizes that could not be linked to a major plasmid incompatibility group. E. cloacae isolates belonged to 6 Rep-types among which two counted for 11 isolates each. The FQ resistant E. cloacae isolates belonged to one clone, whereas the FQ susceptible E. cloacae isolates belonged to four clones. The K. pneumoniae isolates belonged to 9 Rep-types among which one included five isolates.

Conclusion

This study is the first molecular characterization of ESBL-producing isolates from neonatology units in Madagascar, a country with limited epidemiological data. It revealed an important multi-clonal dissemination of CTX-M-15-producing isolates reflecting both the high community carriage and the very early nosocomial contamination of the neonates.

Flow diversion of bifurcation aneurysms is more effective when the jailed branch is occluded: an experimental study in a novel canine model

BACKGROUND

Flow diverters (FDs) are increasingly used for bifurcation aneurysms. Failure of aneurysm occlusion may be caused by residual flow maintaining patency of the jailed branch along with the aneurysm. Our aim was to test whether endovascular occlusion of the jailed branch could improve efficacy of flow diversion of bifurcation aneurysms.

MATERIALS AND METHODS

Sixteen wide-necked lingual-carotid artery bifurcation aneurysms were created in eight canines. Patent aneurysms were randomly allocated 4 weeks later to flow diversion combined with jailed branch occlusion using coils and/or Onyx (n=6) or flow diversion alone (n=8). Angiographic results of aneurysm occlusion at 3 months were scored using an ordinal scale. Pathology specimens were photographed and neointimal coverage estimated using a semiquantitative scoring system.

RESULTS

Fourteen aneurysms were patent at 1 month. FD deployment was successful in all cases but, at 3-month follow-up, three devices had prolapsed into the aneurysm. None of the bifurcation aneurysms treated with FD alone were occluded at 3 months. Endovascular branch occlusion combined with flow diversion significantly improved aneurysm occlusion rates compared with flow diversion alone (median angiographic scores 2 vs 0: p=0.0137). Flow-limiting parent vessel stenosis was not observed in any arteries. Devices were covered with thick neointima in most cases, but patent aneurysms were associated with leaks or holes in the neointima covering the aneurysm neck.

CONCLUSIONS

Treatment failures following flow diversion of bifurcation aneurysms can be caused by persistent flow to the jailed branch. Branch occlusion combined with flow diversion may improve angiographic occlusion scores of a canine bifurcation aneurysm model.

Inter- and Intrarater Agreement on the Outcome of Endovascular Treatment of Aneurysms Using MRA

BACKGROUND AND PURPOSE

Patients treated with coiling are often followed by MR angiography. Our objective was to assess the inter- and intraobserver agreement in diagnosing aneurysm remnants and recurrences by using multimodality imaging, including TOF MRA.

MATERIALS AND METHODS

A portfolio composed of 120 selected images from 56 patients was sent to 15 neuroradiologists from 10 institutions. For each case, raters were asked to classify angiographic results (3 classes) of 2 studies (32 MRA-MRA and 24 DSA-MRA pairs) and to provide a final judgment regarding the presence of a recurrence (no, minor, major). Six raters were asked to independently review the portfolio twice. A second study, restricted to 4 raters having full access to all images, was designed to validate the results of the electronic survey.

RESULTS

The proportion of cases judged to have a major recurrence varied between 16.1% and 71.4% (mean, 35.0% ± 12.7%). There was moderate agreement overall (κ = 0.474 ± 0.009), increasing to nearly substantial (κ = 0.581 ± 0.014) when the judgment was dichotomized (presence or absence of a major recurrence). Agreement on cases followed-up by MRA-MRA was similarly substantial (κ = 0.601 ± 0.018). The intrarater agreement varied between fair (κ = 0.257 ± 0.093) and substantial (κ= 0.699 ± 0.084), improving with a dichotomized judgment concerning MRA-MRA comparisons. Agreement was no better when raters had access to all images.

CONCLUSIONS

There is an important variability in the assessment of angiographic outcomes of endovascular treatments. Agreement on the presence of a major recurrence when comparing 2 MRA studies or the MRA with the last catheter angiographic study can be substantial.

Uncertainty and agreement regarding the role of flow diversion in the management of difficult aneurysms

BACKGROUND AND PURPOSE

The role of flow diversion in the management of aneurysms remains unknown. We sought to evaluate the community agreement regarding indications for flow diversion.

MATERIALS AND METHODS

A portfolio of 35 difficult aneurysm cases was sent to 40 clinicians with varying backgrounds and experience. Responders were asked whether they considered flow diversion a treatment option, whether other options were possible, whether recruitment in a randomized trial would be considered, and to select their final choice. Agreement was studied by using κ statistics.

RESULTS

Decisions for flow diversion were more frequent (n = 300, 39%) than decisions to coil (n = 163, 21.2%), to observe (n = 121, 15.7%), to occlude the parent vessel (n = 102, 13.2%), or to clip (n = 66, 8.6%). Sidewall aneurysm morphology was associated with flow diversion as the final choice (P = .001). Interjudge agreement was fair at best (κ <0.3) for all cases and all judges, despite high certainty levels (range, 7.2-8.9 ± 2.0 on a 0-10 scale). Agreement was no better within specialties or with more experience. All patients were judged to have other treatment options. Judges were willing to offer trial participation in 417 of 741 (56.3%) scenarios, more frequently when the aneurysm was sidewall (P = .001) or in the anterior circulation (P = .028).

CONCLUSIONS

Individuals did not agree regarding the indications for flow diversion. There is sufficient uncertainty to justify trials designed to protect patients from the potential risks of premature adoption of an innovation.

[Management of urinary tract infections in children. Recommendations of the Pediatric Infectious Diseases Group of the French Pediatrics Society and the French-Language Infectious Diseases Society]

Urine dipsticks have to be used more frequently for the screening of urinary tract infections (UTI) in febrile infants and children (grade A). Confirmation of the UTI by urine culture should prefer other methods of sampling than the urine bag: sampling jet, urethral catheterization, or pubic puncture (grade A). The percentage of Escherichia coli producing extended-spectrum beta-lactamases (ESBL) in children accounts for less than 10 % in France and does not justify revising the 2007 recommendations (grade B). An increase in the use of carbapenems in first-line treatment is a major environmental hazard and exposes the patient to the risk of untreatable infections. For febrile UTI, the expert group recommended: (1) recover the results of susceptibility testing as soon as possible to quickly adapt treatment for possible resistant strains; (2) favor initial treatment with aminoglycosides (particularly amikacin) which remain active in the majority of ESBL strains for patients seen in the pediatric emergency department and/or hospital; (3) ceftriaxone (IV or IM) remains an appropriate treatment for patients seen in the emergency department or outpatient clinic because the percentage of ESBL-producing enterobacteria strains remains low; (4) use oral cefixime (grade B) in nonsevere cases and low-risk patients defined as age>3 months, general condition preserved, disease duration of fever<4 days, no associated comorbidity, and no history of urinary tract infection, uropathy, or prior antibiotic therapy in the last 3 months; (5) oral relay for parenteral treatment is guided by in vitro susceptibility testing, in an attempt to reduce the use of oral cephalosporins to limit the selection of resistant bacterial strains. The total duration of treatment recommended is usually 10 days. Except for special circumstances, there is no need to prescribe retrograde cystography or antibiotic prophylaxis after a first febrile urinary tract infection. For cystitis, the panel recommends systematic urinalysis and initial prescription before the results of the urine culture of one of the three following oral antibiotics: amoxicillin-clavulanate, cotrimoxazole, cefixime. The total duration of antibiotic treatment is 5days to tailor treatment based on clinical progression and antibiotic susceptibility.

Susceptibility vessel sign on T2* magnetic resonance imaging and recanalization results of mechanical thrombectomy with stent retrievers: a multicentre cohort study

BACKGROUND AND PURPOSE

The susceptibility vessel sign (SVS) on T2*-weighted magnetic resonance imaging has been reported in several studies as a negative predictor of early recanalization after intravenous thrombolysis. The meaning of SVS regarding the results of mechanical thrombectomy with stent retrievers was investigated.

METHODS

Susceptibility vessel sign presence and length were studied in 153 acute ischaemic stroke patients (82 men; mean ± SD age 59 ± 17 years, baseline National Institutes of Health Stroke Scale score 17.2 ± 6.5) from three stroke centres, treated with either mechanical thrombectomy alone (n = 84) or bridging therapy (n = 69). Variables were compared between recanalizers, defined as thrombolysis in cerebral infarction (TICI) scores ≥2b, and non-recanalizers (TICI<2b).

RESULTS

The SVS was present in 113 (73.8%) patients. There was no association between the presence of SVS and recanalization, obtained in 86 (56.2%) patients, in the whole population [odds ratio (OR) 1.24, 95% confidence interval (CI) 0.53-2.92, P = 0.84) and in treatment subgroups (bridging: OR = 0.91, 95% CI 0.29-2.87, P = 1.0; thrombectomy alone: OR = 1.85, 95% CI 0.48-7.16, P = 0.54). However, in SVS+ patients, recanalization decreased with SVS length (OR 0.94 for each additional mm, 95% CI 0.89-0.99; P = 0.02).

CONCLUSIONS

The success of recanalization in acute stroke patients treated with stent retrievers was related to thrombus length but not to the presence of SVS.

Dual-lumen balloon catheters may improve liquid embolization of vascular malformations: an experimental study in Swine

BACKGROUND AND PURPOSE

Liquid embolic agents are increasingly used to treat vascular malformations. We sought to assess embolization with these agents by using a dual-lumen balloon catheter in an experimental setting.

MATERIALS AND METHODS

Eighteen injections of liquid embolic agents were performed in the rete mirabile of swine. We used 3 methods to control liquid embolic agent reflux: 1) dual-lumen balloon-catheter (group A, n = 8); 2) injection of liquid embolic agent after proximal n-BCA plug formation through a second microcatheter (group B, n = 4); and 3) standard liquid embolic agent injection (group C, controls, n = 6). The following outcomes were graded by using ordinal scales by angiography, macrophotography, and radiography of retia after euthanasia: 1) angiographic and pathologic extent of liquid embolic agent embolization of the rete, 2) reflux of liquid embolic agents in the parent artery, and 3) density of liquid embolic agents in the proximal rete. Technical complications were also recorded. A successful injection was defined as an embolization that reached the contralateral rete without reflux into proximal external branches. Exact logistic regression analyses were performed to compare groups.

RESULTS

There were significant differences among groups for reflux (P = .029) and liquid embolic agent density in the proximal rete (P = .014), while extension to the contralateral rete did not reach statistical significance (P = .07). Injections differed among groups (P = .004), with dual-lumen balloon-catheter injections more frequently successful compared with control injections (P = .019).

CONCLUSIONS

Dual-lumen balloon catheters allowed better liquid embolic agent injections than standard injections.

[Variability in decision-making for treatment choice of intracranial aneurysms]

OBJECTIVES

To measure the variability in choosing treatment options in different clinical situations involving intracranial aneurysms.

MATERIALS AND METHODS

A questionnaire regarding 25 clinical cases was presented via visual projection, to attendees of the Congrès de la Société française de neurochirurgie et de la Société de langue française de neurochirurgie held in Toulouse from May 9th to May 12th, 2012. The audience (n=59) consisted of 58 neurosurgeons and one neuroradiologist. A minority of them (29.2%) stated that they specialized in vascular neurosurgery. The questionnaire dealt with 25 illustrative clinical cases, in which age, gender, and clinical context were provided along with the corresponding angiographic image of the aneurysm. The questionnaire asked whether the physician would have proposed treatment, and if so, which type of treatment (clip, coil or other). In addition, the physician had to indicate, on a scale of one to ten, the degree of confidence they had in their decision.

RESULTS

For one-third of the cases, there was at least 10% of the respondents who opted for a decision opposite to the one of the majority. For 41.7% of the cases, the proportion of respondents who opted for the clip was not significantly different from the proportion of those who opted for the coil.

CONCLUSION

Even in a relatively homogenous group of physicians, there were significantly diverging opinions regarding the management of cerebral aneurysms. This demonstrates the need for evidence-based data from controlled randomized studies.

Decline in antibiotic resistance and changes in the serotype distribution of Streptococcus pneumoniae isolates from children with acute otitis media; a 2001-2011 survey by the French Pneumococcal Network

Streptococcus pneumoniae is an important cause of acute otitis media (AOM). The aim of this study was to evaluate trends in antibiotic resistance and circulating serotypes of pneumococci isolated from middle ear fluid of French children with AOM during the period 2001-2011, before and after the introduction of the PCV-7 (2003) and PCV-13 (2010) vaccines. Between 2001 and 2011 the French pneumococcal surveillance network analysed the antibiotic susceptibility of 6683 S. pneumoniae isolated from children with AOM, of which 1569 were serotyped. We observed a significant overall increase in antibiotic susceptibility. Respective resistance (I+R) rates in 2001 and 2011 were 76.9% and 57.3% for penicillin, 43.0% and 29.8% for amoxicillin, and 28.6% and 13.0% for cefotaxime. We also found a marked reduction in vaccine serotypes after PCV-7 implementation, from 63.0% in 2001 to 13.2% in 2011, while the incidence of the additional six serotypes included in PCV-13 increased during the same period, with a particularly high proportion of 19A isolates. The proportion of some non-PCV-13 serotypes also increased between 2001 and 2011, especially 15A and 23A. Before PCV-7 implementation, most (70.8%) penicillin non-susceptible pneumococci belonged to PCV-7 serotypes, whereas in 2011, 56.8% of penicillin non-susceptible pneumococci belonged to serotype 19A. Between 2001 and 2011, antibiotic resistance among pneumococci responsible for AOM in France fell markedly, and PCV-7 serotypes were replaced by non-PCV-7 serotypes, especially 19A. We are continuing to assess the impact of PCV-13, introduced in France in 2010, on pneumococcal serotype circulation and antibiotic resistance.